I have always been fascinated with the idea that the left and right sides of the brain have unique “personalities” and that by learning more about these differences one might achieve better brain balance. Apparently, however, a lot of what pop psychology has fed us about these characteristics over the past three or four decades is not deeply rooted in science. Iain McGilchrist, former Oxford literary scholar, left the world of poetry to study psychiatry and dig into what exactly is going on in the two hemispheres of the brain. In his book, The Master and His Emissary, he takes a deep look at new research on the brain and sets forth an intriguing theory about societal focus on left brain achievements at the expense of the skills of the right brain.

Before you nod your head and say, ah yes, I remember, the right side of the brain is creative and emotional and the left side is analytical and logical, hold up.

It turns out that both hemispheres are creative and both sides are analytical. Rather than each side of the brain taking on different tasks, it turns out that they tackle the same tasks, but do so in different ways. What’s new here is perspective.

If you had the opportunity to hold a brain you might naturally hold one hemisphere in each hand. You might also notice that the two halves are connected quite firmly by a sturdy tract of tissue called the corpuscallosum, a term that literally means “tough body.” When I was in school we were taught that nerve fibers crossed through the corpus callosum so the two hemispheres could communicate with each other. What scientists have learned since is that one of the main functions of the corpus callosum is inhibition, acting a bit like a traffic light regulating the flow of collaboration between the two.

The ratio of the corpus callosum to the hemispheres of the brain has changed over the course of evolution. This shift highlights the fact that the brain has become more divided and asymmetrical. If you look closely again at the brain in your hands you will see that the frontal lobe on the left extends beyond the right and the occipital lobe on the right extends beyond the left.

So what does all this mean?

We now know that an animal relies on it's left hemisphere to successfully deal with what it knows is important, for example grabbing a piece of food, or building a home. At the same time, the animal uses it’s right hemisphere to stay alert to possibilities of anything that might happen, such as a sudden danger or opportunity for romance.

In humans also the left hemisphere has a laser focus on the details. It has no ability to see the big picture, or imagine how things might be. It is focused on what is known, such as a red apple which should be grasped and eaten.

Nuance, humor and metaphor are lost on the left hemisphere and indeed a person who has suffered a right sided brain injury may lose their ability to read between the lines, laugh at a subtle joke or imagine what might happen next.

The right hemisphere, on the other hand, takes a broad assessment of the environment, with an awareness of possibilities and an ability to calculate variabilities. It understands context and makes sense of emotional expressions. It sees how we fit into our environment and the role we play to contribute to the greater whole.

The right hemisphere takes in the meaning of life, rather than focusing primarily on the mechanical. While the left sees the body as an assemblage of parts, the right sees the body as a human being, part of a family, community and population.

The left side of the brain interprets things very literally. The ability to understand body language or vocal emphasis are lost without right side brain function. It turns out that the right side of our brain has enough of the big picture to value what the left brain has to offer. The left brain, on the other hand, has too narrow a perspective to understand what the right brings to the table.

A phenomenon of denial becomes evident when someone suffers a right hemispheric stroke which can leave a person completely unaware of the deficits left by the brain injury. In this case they may even deny that anything is wrong. Because of this it is easier to rehabilitate someone with a left hemispheric stroke than a right. Without right-sided brain function one cannot see how the parts of the body work together and the sense of body image is lost.

The world of the left hemisphere is a closed system, says McGillchrist, based on what is known and immediate. It can achieve perfection at the price of emptiness. In today’s world, he claims, our reverence for the achievements of the left side of the brain has diverted us from happiness and left us with resentment, loneliness and an “explosion of mental illness.”

Our over reliance on the left side of our brain has left us without the tools we need to take the wealth of information that constantly bombards us and use it in a way that is truly wise.

We now prioritize the virtual over the real thing, convincing ourselves that the technical world is authentic.

The left hemisphere is very convincing because it cuts off anything that disagrees with or distracts it from what it is laser focused on. This is where the title of McGilchrist’s book comes in. Based on an ancient fable in which an arrogant emissary, who believes he is smarter than his master, adopts his master's cloak and impersonates him, to no good end. The master, he explains, is the right side of the brain. The emissary is the left. The master sees the world with wisdom - with a broader perspective as a world of individual living beings, ever-evolving and interconnected and never perfectly known.